Port Scanner
Check which TCP ports are open on any host or IP address
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This tool only scans well-known ports on public hosts. Private and reserved IPs are blocked.
Frequently Asked Questions
A port scanner checks which TCP ports on a server are open and accepting connections. Ports are numbered endpoints (0–65535) that allow different network services to run on the same server. Port 80 is HTTP, port 443 is HTTPS, port 22 is SSH, etc. Open ports indicate running services; closed ports mean nothing is listening there or a firewall is blocking the connection.
Open: A service is actively listening on the port and the TCP connection succeeded. Closed: The port is not open — either no service is running on that port, or a firewall is dropping/rejecting packets. This tool uses TCP connect scanning — if the connection is established within the timeout, the port is marked open.
Port scanning your own servers is always legal. Scanning third-party servers without permission may be illegal in many jurisdictions and is a violation of most hosting terms of service. This tool is intended for scanning your own public-facing servers to audit your firewall configuration. Only scan servers you own or have explicit permission to test.
Each closed/filtered port must wait for a TCP connection timeout (1.5 seconds per port in this tool). For the Top 50 preset, a host with mostly closed ports could take up to 75 seconds. Open ports respond instantly. Firewalls that drop packets (rather than send a TCP RST) cause the most delay. Use the "Common" preset for faster results.
For a web server, you typically want port 80 (HTTP) and 443 (HTTPS) open, and everything else closed. Common security concerns: port 22 (SSH) should be restricted to known IPs, port 3306 (MySQL) and 5432 (PostgreSQL) should never be publicly open, port 3389 (RDP) is a frequent brute-force target. Open database and admin ports on public servers are a serious security risk.
scanme.nmap.org is a server maintained by the Nmap project specifically for port scanning tests. It has explicit permission for the public to scan it, making it a safe target for testing port scanners. Ports 22 and 80 are intentionally open on that host.About This Port Scanner
This free online Port Scanner performs TCP connect scans on any public host. Select from presets (Common, Top 50, Web, Database, Mail) or enter a custom port list. Results show each port's status and the associated service name. Private and reserved IP addresses are blocked to prevent abuse.
Common Ports Reference
| Port | Protocol | Service |
|---|---|---|
| 22 | TCP | SSH |
| 25 | TCP | SMTP |
| 80 | TCP | HTTP |
| 443 | TCP | HTTPS |
| 3306 | TCP | MySQL |
| 5432 | TCP | PostgreSQL |
| 6379 | TCP | Redis |
| 27017 | TCP | MongoDB |
Port Ranges
| Range | Category |
|---|---|
| 0–1023 | Well-known / System ports |
| 1024–49151 | Registered ports |
| 49152–65535 | Dynamic / Ephemeral ports |
